In large assembly or manufacturing plants, as many as five thousand machines may be grouped into one hundred and fifty stations. Many plants are substantially automated, where one manufacturing staff person may operate as many as eight to ten machines. Additionally, a large plant may have approximately twenty maintenance staff per shift.
For many different reasons, a machine may cease functioning. Most often, the machine has a small malfunction, requiring only a press of its reset button to resume operation. There may be many reasons for the small malfunction. In fact, even though a reset most often may return a machine to its functioning status, there are as many as one thousand fault codes associated per machine. A fault code is an industry term to categorize the cause of a problem with a machine. Much like in a modern automobile, sensors are disposed in a machine to detect when out of the ordinary situations occur. In the case of an automobile, for example, if a door is left ajar, a fault code will be generated to alert the occupant that a door is ajar. Fault codes, when generated, may be electronically sent to a central location when a machine stops operating.
In a large plant, when one machine fails, its entire station may stop operating. As a result, parts to be processed by the machine or station may accumulate, with machines feeding the halted machine becoming blocked because the upstream buffer has filled. Moreover, parts discharged for further processing by a downstream machine may drain from the downstream buffer, with machines drawing from it becoming starved. The impact of a downed machine or station can quickly spread to other machines and stations of the production line.
When a machine stops functioning, a light atop the machine will flash red and project sound signals. Furthermore, a maintenance staff member may have an indication of a stopped machine via a notice sent to the maintenance staff member's PDA. The maintenance staff member must then go, typically on foot, to the stopped machine to manually press a reset button on the machine. Most of the time, manually pressing the reset machine cause the machine to restart without incident Once the halted machine is recognized, stoppage is usually rectified in less than three to four minutes.
The time it takes for the maintenance staff member to manually reset the machine isn't typically substantial. However, in a typical sixteen hour day in a plant of the size previously described, there are typically one thousand fault codes generated.
Situations that can be fixed by pressing the reset button include, but are not limited to that a part arrives one-tenth of a second too late to its position within the machine; that the machine's clamping mechanism did not completely clamp the part; a switch temporarily failing to detect the presence of a part; a part of being temporarily jammed, a safety stop being triggered by breaking a light beam or pressing a palm button.
The maintenance staff is better utilized carrying out its primary task of maintaining the machines with preventative maintenance. Currently, a skilled tradesperson is required to perform such manual resets because their expertise is required to evaluate the situation. Maintenance staff's primary task also includes significant equipment failures.